Expansion pulley



July 14, 1925.

J. s. Howe:

EXPANSION PULLEY Filed .my 24, 1922 Patented July `14, 1925.

l UNITED STATES EATENT oFF-ICE.

JOSEPH B. HOWE, 0F WORCESTER, I'IASSCHSETTS, ASSIGNOR TO GEORGE S. HAR'- WOO'D & SON, OF BOSTON, MASSACHUSETTS, A COPARTNERSHIP CONSISTING OF y SYDNEY HARWOOD AND JOHNVH. HAROOD.4 Y

. EXPANSION PULLEY.

Application filed .Tuly/L, 1922. Serial No. 577,007.

Pulleys of this type are particularly useful in the operation'of certain text-ile machinery Where it is necessary to drive the fibre delivering elements of one machne at a speed accurately related to the speed of movement of the fibre receiving elements of a succeeding machine. In such cases itis common to connect the drivingmeans for suoli delivering and receiving elementsby means of a belt engaging an expansible pulley, and varying the effective diameter of the latter to adjust the speed of one of such elements relatively to the other.

Objects of the present invention are to provide a pulley of the above type which is free running and substantially noiseless in operation even at high speeds; capable of retaining any given adjustment without necessitating the `use of a lock nut, set screw, orequivaleiity device; comprising a minimum number of parts; and which is strong and substantial While relatively cheap to manu-V facture. V

In the accompanying drawings one sp'ecilic embodiment of the invention is illustrated by way of example and in such draw# ings Fig. 1 is a diametral cross section of the complete pulley device, the parts being Vshown in fully contracted position;

Fig. 2 is a vertical cross section on the line 2-f2 of Fig. 1; v j,

Fig. 3 is an end elevation of the expand ing device `forming part of the pulley; v i j Fig, Llis a cross section onthe line L1 4 of Fig. 1; and j Fig. 5 is an enlarged fragmentary cross section on the line 5 5 of Fig. 2, certain parts being omitted.` v

Referring to thefdraivings, the numeral 1 indicates a v-supporting shaft having a shoulder at 2y and a portion 3 of somewhat reduced diameter' to the left 0f such shoulder, as viewed in Figure 1. .i l

The outer end of theportion 3 is externally screw threaded at 4, and an anti-fricV tion thrust bearing is mounted upon the rej duced portion 3 of the shaft adjacent to the shoulder 2,.such bearing comprising the col-L lars 5, 6 and the interposed balls 7. A hub S'is mounted .to turn freely upon the re-L duced portion 3 of the shaft, one end 9 of such hub bearing against thecollar 6. The opposite end of the hub is provided With an outstanding flange 10 which is dished at its central portion as indicated at 11, and provided Vwith a radial guard flange '12 serving toyprevent displacement of the belt during operation of the pulley.` A pinion 13 is secured to the hub 8 in any desired manner.

Projecting frenil the flange 10 at the innerV vside, thereof, that is to say'that yside which is opposite the hub 8, is an annular flange 14 extending' axially of the shaft, said flange being provided with `a plurality of radial openings such as 1 5 therethrough. Thesev openings are preferably of angular outline,A being convenientlyy formed by breaching a circularV drill hole with a square breach, one vside 16 of each opening lying substantially in the plane of the inner radial surface 17 of the flange 1() as indicated by Way ofeiiample in Fig..5. The openings 15 are spaced equally about the periphery of the member 14, and in such openings aie loosely fitted stems 18 constil tuting portions of radially movable pulley,

segments which also comprise the arcuate rim members 19. These stems bear against thesurface 17 of the flange 10 and are guided thereby." i v f j' Each' of the stems is provided with' an opening such vas 20, suoli openings serving for the reception of the oppositev ends 21, 22 `respectively of springs 23 of hairpin type interposed in vthe kalternate spaces between stems 18.. The springs 23, at their central portions, are coiled about fixed pins 24. projecting inwardly from the flange l10. As thus arranged the opposite ends 21, 22 of the springs bear against the stems of adjacent segments and tend to move'such segments radially yinvvaid toward the shaft, thus contracting the pulley. l'

l. (l Ii An expanding vdevice 25 yisgmounted t slide upon the shalt 3, such device comprising an active cam portion 2G of substantially truste-conical form and 'an inactivefordwell portion 27 of Vsubstantially'cylindrical forni coaxial with such conical portion and projecting from the smaller end of 'the latter. The cylindrical portion 27 is provided-'With a series ol radially outstanding, axially ex-V tending ribs 2S corresponding in'n'ii'ii'iber'toA the segments of the pulley, suoli ribs being; continued,I as' indicated lat 29,' longiti'idii'i'allyf ofY the peripheral surface of the conical member Theinner 'end oiieach' stem 18 is provided with an'a'X'ia'l slot interengagi'ng ,withA -a rib 28 or the' continuation 29 thereof,

yinga flange 37' constituting a hand wheel' whereby thenut'nmy betur'ned. The inner end ofV the nut 36 engages thefcollar Saa-nd by lturningsuch nut, salidcollar'iscaused to move longitudinally'oi th'esh'alt, being pre# vented 'from' rotating upon the shaftb'y'th'e engage'inent'othe feather '34 witli'tlie splinef 33. When" the pulleyI is' fully' contracted', the inner Vends ofthe 'severalstei'ns l8- bear'- against the .dwell portion v27 *ofthe-expand# ingV device, the" -springs'23"`s`erv'ing 'to press' such" stems against" such cylindrical dwell portion' with suilicient' force to prevent' the accidental' removal of" they wedge'y device iroi'n'b'etw'een the steins. Then it`is"desir' ed to expai'id'tlie pulley,tli`e hand wheel 37 is' turned, c'aus'ing'the "nut 36 to oicetli'ey collar' 35 and the` thrust bearinglongitudinally of the shaft. The expanding' device 25' is thus' mo-'ved'nbodily'along'the shaft, bringing the' conical caniportion thereotinto' operative engagement with the inner ends o'f'thesev'# eral stems 18, 'thus ,forcing'tli'e' segmeiitsof the pulley outwardly, and inc'reasingv" the effective diameter of the sanie The coinpol nent' ci force"tending to', move' the 'pulley longitudinally ofthe' shaft during-fits'a-dl justinentv` is' opposed by thev antifri'ction bearings so" that the' pulleyfis'freetof :turni up'on'" the' 'shaft-'regardless' ofI tlio' 'position ol adjustment' ofi its parts. lllor'eolve'r," byy ltlie' provision or the splnjed. collar 'the turn; ing o'f the pulley'up'o'n' the'sli'aft has' n'o'ellect upon' the'nut 3G such as might cause Suclinut to turn inv one" direction or the other; lt'isthusclcar that turning "of the nut37 serves to adjust the pulley parts in tli'e' desired manner and that suoli adjust ment is, maintained without necessitating the einployinent'ol a' set screw or lock nut for holding the Vnut 36 in adjusted position. pulley in -accordance with the retraction oi the nut 36, such springs forcing the expanding deviceoutwardly until the ends oi the stems come into contact with the cylindrical dwell portion thereof. Further movement of the latter Vdevice is thusprevented by the lrictional engagement of the endsv o'l the stems with suoli cylindrical portion and ff even if" the nut 36'k sliouldv be entirely're` moved, the structural 'integrity 'ofthe pulley is 'not destroyed although the pulley becontinuously subjected to vibrationor .careless handling. i i

The pulley as thus 'constructed contains a minimum number of parts, whileiat'the same time' providing lor great accuracy in adjust# ment,` even while the puflley is running, bv"

the' manipulation of a single element. fis eafch of the segments o'lthepulley is contir'i'iiouslyy under control ofic one of the spring members and as such springs are olsu'lficient strength' 'to' overcom'eitlie action ol centritui gal force' atany spe'e'dat which the pulley stantially radial directions against parts" of the'seginents 'disposed vat eitherV side ofthe respective springs:y

j 2.' A11-'expansion pulley comprising a plu ra'lity oflradially movable segments each having a rim and a radially directed stem; kandfaspring of' hair `pin typedisposed in each alternate sp 'ace lbetween Asaidisten'is and liavingits endseng'aging elements-"of" the adjacent stems.

3'. Anex'p'ansionpulley comprising ap'air of'radially movable segmentsI each having-'a gu'idingste'ni, and aha-ir pin spring interposed between sa'id stems" and havin'n' its central portion coiled about a relatively fixed' stud, and' its end portions engaging openings' in the' respective stems.

'2liV An' expansible pulley comprising a radial guide lange,.a plurality of? segments each 'having'a-radially directed guiding stein slidalolyenga'ging the guide flange, vanexpanderl device comprisii'i'gv aA substantially conicalmei'nber and a cylindrical member The springs 23 serve to contract thecoaxial therewith and extending from the smaller end thereof, said cylindrical member constituting an abutment forthe inner ends of the several guiding stems when the pulley is fully contracted, and a spring disposed in each alternate space between adjacent guide stems, each spring bearing against a relatively fixed part carried by the guide flange and also against the guide stems defining the opposite sides of said space, the several springs cooperating to contract the pulley.

5. An expansible pulley comp-rising a radial guide flange, a plurality of radially movable segments each having a guide stem slidably engaging the guide flange,each of said stems being provided with an opening intermediate its ends, a spring of hairpin type disposed in each alternate space between adjacent guide stems, opposite ends of each spring being disposed in the open-l ings respectively of the guide stems deiining the space in which the spring is located, an axially movable expander member comprising a part of frustosconical form and a substantially cylindrical member coaxial therewith and projecting from the smaller end thereof, said latter part constituting an abutment to limit inward movement of the segments when the pulley is fully contracted by the several springs, and means for moving said member to expand the pulley.

6. An expansible pulley having a plu-` rality of independent rim members each having a radially directed guide stem, a centrally disposed and axially movable expander device comprising a cam element of frusto-conical form and a substantially cylindri- Caldwell element extending axially from the smaller end of said iirst element, axially extending ribs projecting from the peripheral surface of said cylindrical element, continuations of said ribs also projecting from said conical element, the several ribs engaging slots in the ends of the respective guide stems, and means for moving said ex ander device.

An expansion pulley comprising a hub, a flange projecting radially therefrom, said flange having an integral, axially projecting annular member provided with a plurality of angular, radial openings, one side of each opening lying substantially in the plane of the radial inner surface of theV flange, a plurality of rim members each having a guiding stem fitting one of said openings and slidably engaging said inner surface of the flange, wedge means for forc ing said stems outwardly, and resilient means independent of the wedge means normally tending to move said guide stems inwardly. f

8. A n expansible pulley device comprising a shouldered shaft having screw threads at one end, an anti-friction thrust collarV bearing against the shoulder of the shaft, a hub turning freely on the shaft and having one end in engagement with said collar, a radial flange outstanding from thel hub, radially movable rim l'members supported `by the flange, springs normally tending to move said rim members radially inward, an expander device slidable axially of the shaft for moving the several rim members outwardly, an antifriction collar bearing against the outer end of said expander device, and a manually operable-nut engaging the screw threaded portion of the shaft and constructed and arranged to force the last named. antfriction collar and the expander device axially of the shaft.

Signed by me at Boston, Mass., this 19th day of July 1922. i

JOSEPH B. HOVE. 

